Only individuals, and not the Pakistan government, are involved in nuclear proliferation, US Deputy Secretary of State Richard Armitage has said.

The US has held significant discussions with the Pakistan government, which has been "very forthright in the last several years with us about proliferation", Armitage, who was interviewed by Japan's Asahi Shimbun, said.

"The question of [Pakistani scientist] A Q Khan [who sold nuclear secrets] is one that is under investigation by Pakistani authorities. I will let them make any comments they want to about it. I don't care to talk about that, nor any intelligence we may have on it," he said.

He added: "I think there is a growing realisation that [President] Pervez Musharraf is the right man in the right time in the leadership of Pakistan. The very fact that some people are trying to assassinate him indicates to me that he is being successful in trying to bring Pakistan into a modern and productive life, both in South Asia and more broadly in the world."